Input surge current testing device

Abstract

The utility model discloses an input surge current testing device which comprises an AC input end, the AC input end is sequentially connected with a bridge rectifier, a filtering energy storage capacitor bank and a surge test output end, and a discharging circuit is connected between the filtering energy storage capacitor bank and the surge test output end in parallel. And the operation switch SW1 is used for controlling connection and disconnection between the filtering energy-storage capacitor bank and the surge test output end. The surge current testing device is connected in series between an alternating current power supply and a power panel to be tested, and provides instantaneous high-voltage large-current output for the power panel to be tested through the independent rectification part, the energy storage capacitor part and the corresponding control switch, so that an accurate surge current testing result can be obtained, and a high-specification adjustable AC power supply does not need to be upgraded for testing.

Description

Technical Field

[0001] The utility model relates to the technical field of power supply testing, in particular to an input surge current testing device. Background Art

[0002] Now the requirements for the functions and performance of the power supply as the core of power conversion in electronic products are getting higher and higher. Taking TV sets as an example, the power supply part especially needs higher reliability, and related tests are an important guarantee in the development stage. Inrush current test is an important routine test related to safety. The reason for the surge current is the strong pulse generated by the charging of the input filter capacitor when the power supply is connected to the power grid. At present, there are the following problems in testing the input surge current of the switching power supply: 1. Using the mains as the power input cannot guarantee a phase angle of 90° or 270° to obtain the maximum input voltage and thus the maximum current. The power capacity of the commonly used programmable AC SOURCE device does not meet the requirements. There is a maximum output current limit during the test, and it may not be possible to test the maximum surge current. If you want to correctly measure the surge current of the product, you need a model with a capacity of at least 30KVA, which is expensive and bulky. For this type of special equipment, due to the small demand, there are no existing products on the market, and the relevant device parameters need to be selected according to the actual situation; 2. In actual testing, there is a certain risk of manually discharging the energy storage capacitor of the device, which is easy to cause harm to the tester and affect the test efficiency. Using a multimeter to confirm whether the capacitor bank is fully charged and fully discharged is also a cumbersome and dangerous operation. Utility Model Content

[0003] The purpose of the utility model is to provide an input surge current testing device, which is used to solve the problem in the prior art that due to the output current limitation of the programmable AC SOURCE device, the maximum surge current may not be tested, the mains power is directly tested, and the input voltage cannot accurately reach the maximum voltage value of the 90° or 270° phase output, and the maximum surge current cannot be obtained. It also solves the problem of high risk of manual discharge of the energy storage capacitor of the device.

[0004] The utility model solves the above problems through the following technical solutions:

[0005] An input surge current testing device comprises an AC input end, wherein the AC input end is sequentially connected to a rectifier bridge stack, a filter energy storage capacitor group and a surge test output end, a discharge circuit is connected in parallel between the filter energy storage capacitor group and the surge test output end, and an operating switch SW1 is also included for controlling the connection and disconnection between the filter energy storage capacitor group and the surge test output end.

[0006] A large-capacitance energy storage capacitor is used as the input source of the power supply device under test. Due to the characteristics of the capacitor, the instantaneous discharge current is infinite under ideal conditions. The large-capacity capacitor can achieve high-voltage and high-current output at the output moment, ensuring that the power supply under test is adequately supplied with energy, so that the real surge current can be measured, achieving a more accurate test result than conventional programmable AC SOURCE devices. This utility model patent uses a rectifier bridge as the input voltage of the AC power to rectify, and then provides electrical energy for the capacitor filtering energy storage.

[0007] Furthermore, a safety protection circuit and / or an EMI circuit is provided between the AC input terminal and the rectifier bridge stack. The EMI circuit is used to suppress EMI interference. A safety protection circuit and an EMI circuit are placed at the front end of the rectifier bridge stack to improve the safety of the device and the quality of the input voltage and current.

[0008] Furthermore, the safety protection circuit is one or more of a fuse, a varistor and a thermistor. These protection devices are used to protect the rectifier bridge and the filter energy storage capacitor group at the subsequent stage.

[0009] Furthermore, the filtering energy storage capacitor group is composed of at least two large-capacity and high-voltage electrolytic capacitors connected in parallel, which are used to obtain the maximum DC voltage of the mains input after rectification and filter and store electrical energy. Using them in parallel can increase the capacitance and ensure the maximum surge current.

[0010] Furthermore, an energy storage indicator light circuit is connected in parallel between the filtering energy storage capacitor group and the surge test output terminal.

[0011] Furthermore, the energy storage indicator light circuit includes at least two indicator light units connected in parallel at both ends of the filter energy storage capacitor group, and each indicator light unit includes an LED lamp and a resistor connected in series with the LED lamp. The energy storage indicator light circuit is used to indicate the voltage level of the filter energy storage capacitor group. The resistor is used to limit the current to protect the LED lamp. By taking a suitable value, the service life of the LED lamp can be increased. The use of two groups in parallel can improve reliability. At the same time, because the circuit is directly connected in parallel at both ends of the filter energy storage capacitor group, it can continuously consume the energy in the capacitor. If the discharge circuit fails, it can also discharge slowly to improve safety. By placing a capacitor voltage indicator light circuit, the operator is prompted whether the capacitor has electricity. And a circuit discharge switch circuit is used to quickly discharge the residual voltage charge to avoid direct manual operation.

[0012] Furthermore, the discharge circuit includes a switch SW2, a first resistor and a second resistor connected in series, a third resistor and a fourth resistor connected in series, the first end and the second end of the first resistor and the third resistor are connected respectively, the first end and the second end of the second resistor and the fourth resistor are connected respectively, and the second end of the second resistor and the fourth resistor are connected in series with the switch SW2. The resistors are connected in two series and two parallel to evenly distribute the heat, and this method improves safety. If a single resistor fails, it is still relatively safe.

[0013] Furthermore, the rectifier bridge stack is composed of two groups of full-bridge rectifier tubes connected in parallel, which are used to convert alternating current into direct current voltage. The two groups of full-bridge rectifier tubes can improve the rectification reliability of the device and distribute the heat.

[0014] Compared with the prior art, the utility model has the following advantages and beneficial effects:

[0015] (1) The utility model is connected in series between an AC power supply and a power board to be tested, and provides an instantaneous high-voltage and high-current output to the power board to be tested through a separate rectifier part and an energy storage capacitor part, as well as a corresponding control switch, so that accurate surge current test results can be obtained without the need to upgrade a high-specification adjustable AC power supply for testing.

[0016] (2) The utility model is not only applicable to switching power supply boards of various powers, but also can be used to perform input surge current testing on any device powered by AC. Safety and ease of use are taken into consideration during the design, and input safety protection circuits, EMI circuits, energy storage indicator circuits, capacitor bank discharge circuits, and a variety of AC plugs are designed, which are highly safe and compatible.

[0017] (3) The utility model can easily obtain accurate test results at a low cost.

[0018] (4) The utility model solves the problem that the maximum surge current of the device under test may not be obtained by directly using AC power or using a programmable AC SOURCE device, thereby causing inaccurate testing. According to the electrical characteristics of the capacitor, the current is approximately infinite at the moment of conduction, and the effect is relatively ideal.

[0019] (5) By placing the energy storage indicator light circuit and the discharge circuit, direct discharge operation is avoided. The capacitor voltage can be directly observed through the brightness change of the indicator light. The use of the discharge circuit avoids the risk of short circuit when using other discharge devices, thereby improving safety.

[0020] (6) The structure of this device is relatively simple. Since it does not require a large number of tests, the controller is not used to replace the switch operation, which reduces the complexity of the system. The safety protection circuit and EMI circuit set at the same time improve the safety of the system. Fuses, thermistors, rectifier bridges, resistors in the energy storage indicator circuit, and resistors in the discharge circuit are all considered redundant, which greatly improves the reliability of this device. It is easy to maintain and has a wide range of uses. As long as the device is powered by AC, the input surge current test can be performed with this device in theory. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a principle block diagram of the utility model;

[0022] Figure 2 It is the circuit principle diagram of the utility model;

[0023] Figure 3 This is a schematic diagram of the test environment of the utility model;

[0024] Figure 4 This is a schematic diagram of the traditional surge current test using the CHROMA6530 programmable power supply;

[0025] Figure 5 It is a schematic diagram of the surge current test results of the utility model. DETAILED DESCRIPTION

[0026] The present invention is further described in detail below in conjunction with the embodiments, but the implementation manner of the present invention is not limited thereto.

[0027] Embodiment 1:

[0028] Combined with Figure 1 As shown, an input surge current testing device includes an AC input end, which is sequentially connected to a rectifier bridge stack, a filter energy storage capacitor group and a surge test output end, a discharge circuit is connected in parallel between the filter energy storage capacitor group and the surge test output end, and also includes an operating switch SW1 for controlling the connection and disconnection between the filter energy storage capacitor group and the surge test output end.

[0029] A large-capacitance energy storage capacitor is used as the input source of the power supply device under test. Due to the characteristics of the capacitor, the instantaneous discharge current is infinite under ideal conditions. The large-capacity capacitor can achieve high-voltage and high-current output at the output moment, ensuring that the power supply under test is adequately supplied with energy, so that the real surge current can be measured, achieving a more accurate test result than conventional programmable AC SOURCE devices. This utility model patent uses a rectifier bridge as the input voltage of the AC power to rectify, and then provides electrical energy for the capacitor filtering energy storage.

[0030] like Figure 2As shown, a safety protection circuit (fuse FP101, fuse FP102, varistor RVP101, thermistor RTP101, thermistor RTP111, thermistor RTP112, thermistor RTP113 and thermistor RTP114) and / or an EMI circuit (including common mode inductor FLP101, common mode inductor FLP102, X capacitor CXP101 and X capacitor CXP102) are arranged between the AC input end (including the first terminal CNP101 and the second terminal CNP103) and the rectifier bridge stack. The EMI circuit is used to suppress EMI interference. The safety protection circuit and the EMI circuit are placed at the front end of the rectifier bridge stack to improve the safety of the device and the quality of the input voltage and current.

[0031] Furthermore, the safety protection circuit is one or more of a fuse, a varistor and a thermistor. These protection devices are used to protect the rectifier bridge and the filter energy storage capacitor group at the subsequent stage.

[0032] Furthermore, the filtering energy storage capacitor group is composed of at least two large-capacity and high-voltage electrolytic capacitors in parallel (electrolytic capacitor CP201 ​​and electrolytic capacitor CP202), which are used for filtering after rectification to obtain the maximum DC voltage of the AC input and store electrical energy. Using them in parallel can increase the capacitance and ensure the maximum surge current.

[0033] Furthermore, an energy storage indicator light circuit is connected in parallel between the filtering energy storage capacitor group (electrolytic capacitor CP201 ​​and electrolytic capacitor CP202) and the surge test output terminal (including the first output terminal CNP201 and the second output terminal CNP202).

[0034] Further, the energy storage indicator light circuit includes at least two indicator light units connected in parallel at both ends of the filter energy storage capacitor group, and each indicator light unit includes an LED lamp and a resistor connected in series with the LED lamp (resistor RP201, resistor RP202, resistor RP203 and diode LED1 are an indicator light unit, and resistor RP204, resistor RP205, resistor RP206 and diode LED2 are an indicator light unit). The energy storage indicator light circuit is used to indicate the voltage level of the filter energy storage capacitor group. The resistor is for current limiting protection of the LED lamp. By taking a suitable value, the service life of the LED lamp can be increased. The use of two groups in parallel can improve reliability. At the same time, because the circuit is directly connected in parallel at both ends of the filter energy storage capacitor group, it can continuously consume the energy in the capacitor. If the discharge circuit fails, it can also discharge slowly to improve safety. By placing a capacitor voltage indicator light circuit, the operator is prompted whether the capacitor has electricity. And a circuit discharge switch circuit is used to quickly discharge the residual voltage charge to avoid direct manual operation.

[0035] Furthermore, the discharge circuit includes a switch SW2, a resistor RP207 and a resistor RP208 connected in series, a resistor RP209 and a resistor RP210 connected in series, the first end and the second end of the resistor RP207 and the resistor RP209 are connected respectively, the first end and the second end of the resistor RP208 and the resistor RP210 are connected respectively, and the second end of the resistor RP208 and the resistor RP210 are connected in series with the switch SW2. The resistors are connected in two series and two parallel to evenly distribute the heat, and this method improves safety. If a single resistor fails, it is still relatively safe.

[0036] Furthermore, the rectifier bridge stack is composed of two groups of full-bridge rectifier tubes (full-bridge rectifier tube BP101 and full-bridge rectifier tube BP102) connected in parallel, which are used to convert alternating current into direct current voltage. The two groups of full-bridge rectifier tubes can improve the rectification reliability of the device and distribute the heat.

[0037] Figure 3 This is an application scenario of the device. The device is connected to an AC input and a power board to be tested. The power board to be tested is connected to an electronic load. The surge current can be detected by a digital oscilloscope.

[0038] like Figure 4 and Figure 5 As shown, Figure 4 This is a schematic diagram of the test results using an adjustable AC power supply such as CHROMA6530. Figure 5 The test diagram of this device shows that there is a power limitation when using an adjustable AC power supply, and the surge current is clipped. When using this device for testing, the voltage rectified by the rectifier bridge is always input at the highest phase. At the same time, the large electrolytic capacitor stores energy after rectification to ensure that the input energy is sufficient and the surge current waveform is complete and true.

[0039] Although the present invention is described herein with reference to the illustrative embodiments of the present invention, the above embodiments are merely preferred embodiments of the present invention, and the embodiments of the present invention are not limited to the above embodiments. It should be understood that those skilled in the art can design many other modifications and implementations, which will fall within the scope and spirit of the principles disclosed in this application.

Claims

1. An input surge current test device, characterized in that: It includes an AC input end, which is sequentially connected to a rectifier bridge stack, a filter energy storage capacitor group and a surge test output end, a discharge circuit is connected in parallel between the filter energy storage capacitor group and the surge test output end, and also includes an operating switch SW1 for controlling the connection and disconnection between the filter energy storage capacitor and the surge test output end.

2. The input surge current testing device according to claim 1, characterized in that: A safety protection circuit and / or an EMI circuit is arranged between the AC input terminal and the rectifier bridge stack.

3. The input surge current testing device according to claim 2, characterized in that: The safety protection circuit is one or more of a fuse, a varistor and a thermistor.

4. The input surge current testing device according to claim 1, characterized in that: The filtering energy storage capacitor group is composed of at least two electrolytic capacitors connected in parallel.

5. The input surge current testing device according to claim 4, characterized in that: An energy storage indicator light circuit is connected in parallel between the filtering energy storage capacitor group and the surge test output end.

6. The input surge current testing device according to claim 5, characterized in that: The energy storage indicator light circuit comprises at least two indicator light units connected in parallel at both ends of a filtering energy storage capacitor group, and each indicator light unit comprises an LED lamp and a resistor connected in series with the LED lamp.

7. The input surge current testing device according to claim 1, characterized in that: The discharge circuit includes a switch SW2, a first resistor and a second resistor connected in series, and a third resistor and a fourth resistor connected in series, wherein the first end and the second end of the first resistor and the third resistor are connected respectively, the first end and the second end of the second resistor and the fourth resistor are connected respectively, and the second ends of the second resistor and the fourth resistor are connected in series with the switch SW2.

8. The input surge current testing device according to claim 1, characterized in that: The rectifier bridge stack is composed of two groups of full-bridge rectifier tubes connected in parallel.

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